This was the first U.S. attempt to achieve impact on the lunar surface. The Block
II Ranger spacecraft carried a TV camera that used an optical telescope that would allow imaging down to about 24 kilometers above the lunar surface during the descent. The main bus also carried a 42.6-kilogram instrument capsule that would separate from the bus at 21.4 kilometers altitude and then independently
impact on the Moon.

Protected by a balsa-wood outer casing, the capsule was designed to bounce several times on the lunar surface before coming to rest. The primary onboard instrument was a seismometer.

Because of a malfunction in the Atlas guidance system (due to faulty transistors), the probe was inserted into a lunar transfer trajectory with an excessive velocity. A subsequent incorrect course change ensured that the spacecraft reached the Moon 14 hours early and missed it by 36,793 kilometers on 28 January. The central computer and sequencer failed and the spacecraft returned no TV
images.

The probe did, however, provide scientists with the first measurements of interplanetary gamma-ray flux. Ranger 3 eventually entered heliocentric orbit.

Key Dates

26 Jan 1962: Launch (20:30 UT)

Status: Partial Success

Fast Facts

Ranger 3 was designed to hit the lunar surface at about 130 to 160 km/hr (80 -100 mph).

It was one of only two Moon missions launched in 1962. Both were part of the Ranger program.

There were a total of nine Ranger spacecraft. The program paved the way for Surveyor landers and, ultimately, the Apollo Moon landings.

People Spotlight

Al HibbsAl Hibbs decided as a five-year-old that he wanted to go to the Moon. He did qualify as an astronaut, but his legacy is in robotic exploration.